.\" Copyright (c) 1990, 1991 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek and the American National Standards Committee X3,
.\" on Information Processing Systems.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
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.\"     @(#)ferror.3	6.8 (Berkeley) 6/29/91
.\"
.\"
.\" Converted for Linux, Mon Nov 29 14:24:40 1993, faith@cs.unc.edu
.\" Added remark on EBADF for fileno, aeb, 2001-03-22
.\"
.TH FERROR 3  2001-10-16 "" "Linux Programmer's Manual"
.SH NAME
clearerr, feof, ferror, fileno \- 检测和重置流状态
.SH "SYNOPSIS 总览"
.B #include <stdio.h>
.sp
.BI "void clearerr(FILE *" stream );
.br
.BI "int feof(FILE *" stream );
.br
.BI "int ferror(FILE *" stream );
.br
.BI "int fileno(FILE *" stream );
.SH "DESCRIPTION 描述"
函数
.B clearerr
清除
.IR stream
指向的流中的文件结束标记和错误标记。
.PP
函数
.B feof
测试
tests the end-of-file indicator for the stream pointed to by
.IR stream
指向的流中的文件结束标记，如果已设置就返回非零值。文件结束标记只能用函数
.BR clearerr
清除。
.PP
函数
.B ferror
测试
.IR stream
指向的流中的错误标记，如果已设置就返回非零值。错误标记只能用函数
.B clearerr
重置。
.PP
函数
.B fileno
检测
.I stream
参数，返回它的整数形式的文件描述符。
.PP
关于对应的非锁定函数，请参见
.BR unlocked_stdio (3)
。
.SH "ERRORS 错误"
这些函数不应当失败，它们不设置外部变量
.IR errno
。(但是，如果
.B fileno
检测到它的参数不是有效的流，它必须返回 \-1，并且将
.I errno
设置为
.BR EBADF
。)
.SH "CONFORMING TO 标准参考"
函数
.BR clearerr ,
.BR feof ,
以及
.BR ferror
遵循 X3.159-1989 (``ANSI C'') 标准。
.SH "SEE ALSO 参见"
.BR open (2),
.BR unlocked_stdio (3),
.BR stdio (3)
